The DIY Open Crank Engine Moped

Anyone can strap a two-stroke engine on a bicycle to create a moped. But [robinhooodvsyou] has created something infinitely more awesome. He’s built an inverted open crank engine on a 10 speed bicycle. (YouTube link)  As the name implies, the engine has no crankcase. The crankshaft, camshaft, and just about everything not in the combustion chamber hangs out in the open where it can be seen and appreciated.

[robinhooodvsyou] started with an air-cooled Volkswagen cylinder. He filled the jug with a piston from a diesel car. Camshaft, flywheel, valves, and magneto are courtesy of an old Briggs and Stratton engine. The cylinder head, crankshaft, pushrods, and the engine frame itself are all homemade.

Being an open crank engine, lubrication is an issue. The crankshaft’s ball bearing is lubricated by some thick oil in a gravity fed cup. Even though the engine is a four-stroke,[robinhooodvsyou] adds some oil to the gas to keep the rings happy. The camshaft and connecting rod use Babbit bearings. While they don’t have an automatic oiling system, they do look pretty well lubricated in the video.

Starting the engine is a breeze. [robinhooodvsyou] created a lever which holds the exhaust valve open. This acts as a compression release. He also has a lever which lifts the entire engine and friction drive off the rear wheel. All one has to do is pedal up to cruising speed, engage the friction drive, then disengage the compression release.

We seriously love this hack. Sure, it’s not a practical vehicle, but it works – and from the looks of the video, it works rather well. The unmuffled pops of that low 4:1 compression engine reminds us of old stationary engines. The only thing we can think to add to [robinhooodvsyou’s] creation is a good set of brakes!

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Measuring Car Engine RPM via the Cigarette Lighter

delorean

Sometimes we forget how many things we can do with a simple oscilloscope. In this video [Ben] uses one that Tektronix lent him to measure his DeLorean engine RPM. By checking the car main ~12V voltage one may notice that the voltage spikes occurring are directly related to the engine speed, as they are created by the inductive kicks from the ignition coils. Obviously the multiplication you have to do to get the RPMs from the number of spikes per second depends on your engine configuration (flat 4, v6…).

The method that [Ben] used was to search for high amplitude spikes on the (AC coupled) car 12V Fast Fourier Transform (FFT) to get a reliable measurement given the many electrical noise sources present in his car. At the end of his video, he however mentioned that it could still be possible to get a good measurement with a simple voltage comparator and a high enough voltage reference.

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An homemade 48cc V8 engine with injection

A few months ago we mentioned [Keith]’s first project in the works, a 1/4 scale V8 engine. Today, we are amazed to see that his engine is finished and running really smoothly. What is even more impressive is that the entire project has been completed on manual mills and lathes. The thread on the Home Model Engine Machinist forum contains his build log in which he details how all the different parts were made. The engine has an electric starter, uses a fuel injection system and [Keith] even made his own injection molds for several plastic parts. The ECU is based on the Megasquirt-II, we guess it must have taken [Keith] many tries before correctly setting its parameters. A video of the engine in action can be viewed after the break.

You can find our previous coverage of this project as well as other miniature engines on this feature from last April.

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Restoring an Industrial Tractor

tractor

[Nickolas] dropped us a tip about a Youtube channel where [stevewatr] documents the restoration of an Oliver 770 tractor through no less than 133 videos. These videos span the last year, starting with finding the tractor in fairly dense undergrowth. He spends quite a bit of time troubleshooting the engine, explaining his thought process, and showing all of the steps he takes to get the tractor running reliably again. He also delves into fixes for the electrical and hydraulic systems.

In his tip, [Nickolas] said he just couldn’t stop watching, and we agree, this is really a fascinating series. One of the things we love about these videos is that [stevewatr] doesn’t filter out his mistakes. That means we get to see his failures and successes… Everything from how jump starting wasn’t possible with a small jumper wire, to getting the engine to start cold without a primer. That’s the beauty of our fail-of-the-week posts. Absorb it all, and you’ll be prepared when you run into related problems yourself.

[stevewatr’s] last video doesn’t show a completed tractor, so we look forward to seeing what happens as the project progresses. Even if you aren’t interested in having a tractor of your own, you can certainly use some of this information while building your own personal mech. Give it a try!

This week on HANDMADE.hackaday

Snap 2013-06-09 at 09.13.04

This week on HANDMADE.hackaday we’ve seen a pretty good variety of skills.

HANDMADE.hackaday.com is growing quickly. Keep sending in those good tips! We have some videos of our own planned as well, keep an eye out for those!

1,200 hours of work results in the smallest v12 engine

[José Manuel Hermo Barreiro] has spent many many hours crafting these tiny engines from hand. Every single piece is custom made specifically for the engine it is going onto. He has created aircraft engines, car engines, and marine engines that all actually run and are the smallest of their kind in the world.

At one point in this video he stands in a room with several engines lined up, all running smoothly and considers that there are possibly over 15,000 hours of work right there in front of him.

Here’s a video specifically about the 12 cylinder construction.

[Thanks Staskazz]

 

Second grade science project: a steam engine

2nd-grade-steam-engine

If you’re looking for a way to let the kids get hand-ons with science this is a perfect example of how to do it. [Erich] wanted to help out with his 7-year-old’s science project. They decided to build a working model of a steam engine but couldn’t find online instructions appropriate for the age group. So the two of them not only pulled off the build, but then they wrote a guide for others to follow. The thing about it is, you really have to understand a concept to teach it to someone else. So we think the write-up is equally important to having actually done the experiment.

Steam can scald you if you’re not careful. But you don’t really need steam to explore the concepts of a steam engine. The main reason to use steam is that it’s a fairly rudimentary way to build pressure which can be converted to motion. For this demonstration the blue balloon provides that pressure. It’s feeding a reservoir that connects to the valve built out of straws. A plastic piston inside pushes against the crank shaft, spinning the cardboard wheel on the left. When the piston travels past the valve opening it releases the air pressure until the machine makes a revolution and is in place for the next push. This is well demonstrated in the clip after the break.

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